Process for converting carbon-based energy carrier material

ABSTRACT

A process is disclosed process for converting a solid or highly viscous carbon-based energy carrier material to liquid and gaseous reaction products, said process comprising the steps of: a) contacting the carbon-based energy carrier material with a particulate catalyst material b) converting the carbon-based energy carrier material at a reaction temperature between 200° C. and 450° C., preferably between 250° C. and 350° C., thereby forming reaction products in the vapor phase. In a preferred embodiment the process comprises the additional step of: c) separating the vapor phase reaction products from the particulate catalyst material within 10 seconds after said reaction products are formed; In a further preferred embodiment step c) is followed by: d) quenching the reaction products to a temperature below 200° C.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a catalytic process of converting acarbon-based energy carrier material to a liquid or gaseous fuel.

2. Description of the Related Art

As the supply of light crude diminishes, alternate materials are beingdeveloped as a source of liquid and gaseous fuels. Alternate materialsbeing considered include mineral energy carriers, such as heavy crudes,shale oils, tars (e.g., from tar sands) and bitumen.

Alternate materials further include waste supplies of synthetic resins.These synthetic resins may be virgin materials, for example rejects frommolding and drawing operations, and used materials, such as recycledpackaging materials.

Yet another, and potentially the most important, source of alternatecarbon-based energy carrier material includes biomass, in particularbiomass containing cellulose, lignin, and hemicellulose.

Processes have been developed for converting these materials to liquidand gaseous fuels. Catalysts have been proposed for use in suchprocesses. Even when catalysts are used, however, the conversionreaction requires relatively high reaction temperatures, often in excessof 450° C. Exposure of the reaction products to these reactionconditions results in a significant deterioration of the reactionproducts. As a result, valuable materials are converted to undesirablematerials such as gas, char and coke, which foul and deactivate thecatalyst particles and reduce the yield of the reaction process.Furthermore bio-oil, which is the main reaction product, is of a poorquality and requires extensive costly treatment for it to be madesuitable as a transportation fuel or a source for high value chemicals.

The present invention provides an improved process for converting acarbon-based energy carrier material to a liquid or gaseous fuel. Theprocess is characterized in that the conversion temperature is less than450° C., preferably less than 400° C., and in that the exposure time ofreaction products to elevated temperatures and to contact with catalyticmaterial is kept short.

SUMMARY OF THE INVENTION

The present invention relates to a process for converting a solid orhighly viscous carbon-based energy carrier material to liquid andgaseous reaction products, said process comprising the steps of:

-   -   a) contacting the carbon-based energy carrier material with a        particulate catalyst material    -   b) converting the carbon-based energy carrier material at a        reaction temperature between 200° C. and 450° C., preferably        between 250° C. and 350° C., thereby forming reaction products        in the vapor phase.

Step a) may comprise the steps of providing particles of thecarbon-based energy carrier material, and coating these particles withsmaller particles of the catalyst material.

In an alternate process, step a) may comprise the steps of (i)contacting the carbon-based energy carrier material with a precursor ofthe catalytic material; and (ii) forming the catalytic material in situ.

In yet another embodiment step a) comprises the step of contacting thecarbon-based energy carrier material with a fluid bed of particulatecatalyst material. Optionally this process step is carried out atelevated temperature. A heat transfer medium may be present.

It is possible to add more catalytic material to step b). This catalyticmaterial may be the same as that added in step a), or it may be adifferent catalytic material.

In a preferred embodiment the process comprises the additional step of:

-   -   c) separating the vapor phase reaction products from the        particulate catalyst material within 10 seconds after said        reaction products are formed;

In a further preferred embodiment step c) is followed by:

-   -   d) quenching the reaction products to a temperature below 200°        C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of one embodiment of a processunit for carrying out a process according to the present invention.

FIG. 2 shows an experimental set-up for conducting pyrolysisexperiments.

FIG. 3 is a schematic representation of a thermobalance.

FIG. 4 shows the DTG curve for pine powder.

FIG. 5 shows the DTG curve for pine powder co-milled with 20% Na₂CO₃.

FIG. 6 shows the DTG curve for pine powder co-milled with 20% MgO.

FIG. 7 shows the DTG curve for pine powder co-milled with 20% calcinedhydrotalcite.

FIG. 8 shows the DTG curve for pine powder co-milled with non-calcinedhydrotalcite.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following is a description of certain embodiments of the invention,given by way of example only.

In one aspect, the present invention relates to a pretreatment ofparticulate carbon-based energy carrier materials so as to make thesematerials susceptible to a conversion to a liquid fuel under relativelymild conditions.

The carbon-based energy carrier materials for use in the process of thepresent invention are solid materials and materials that could beclassified as liquids, but having a very high viscosity. In thisdocument, the materials will be referred to as “solid”. It will beunderstood that, as used herein, the term solid encompasses highlyviscous liquids. In the case of tar sands, the “particles” comprise sandcorns that are coated with tar. For the purpose of the present inventionthese coated sand corns are considered particles of a carbon-basedenergy carrier.

The materials can be formed into particles, which particles tend toretain their integrity at or near ambient conditions of temperature andpressure. Examples of such materials include coal, tar sand, shale oil,and biomass.

Preferably step a) results in an intimate contact of the catalystparticles with the carbon-based energy carrier. One process involvesproviding particles of the carbon based energy carrier material, andcoating these particles with smaller particles of a catalytic material.The coated particles are subjected to thermal treatment, during whichthe energy carrier material becomes sensitized.

Another process for sensitizing the carbon based energy carrier materialis suitable for energy carrier materials that contain a polymer ofphotosynthetic origin. In this process, small particles of an inorganicmaterial are embedded within the polymeric material of photosyntheticorigin. This process is disclosed in detail in our co-pending patentapplication entitled “Method of making a polymeric material ofphotosynthetic origin comprising particulate inorganic material” thedisclosures of which are incorporated herein by reference.

Yet another process for sensitizing the carbon based energy carriermaterial comprises the step of contacting the carbon based energycarrier material with reaction products obtained in step b) of theprocess of the present invention. It will be understood that when theprocess is started no reaction product is yet available. Therefore, atthis stage, the carbon based energy carrier material may be sensitizedby some other method. It is also possible to start the reaction withnon-sensitized material, and carry out the pyrolysis step underconventional conditions of temperature and pressure. For example, thereaction may be started at a temperature of up to 600 degreescentigrade, and a pressure between 1 and five bar. Under theseconditions, relatively large amounts of organic acids and phenolicmaterials are produced. Although this is undesirable from theperspective of the need to make useful liquid fuels, this reactionproduct is practically suitable for mixing with the carbon based energycarrier material for sensitization purposes. Once enough reactionproduct is formed to operate the reaction with a continuous supply ofsensitized material, the pyrolysis conditions can then be changed to atemperature of less than 500 degrees centigrade and, optionally, apressure of less than one bar.

Another embodiment is particularly suitable if the carbon-based energycarrier is a biomass, in particular solid particulate biomass. In thisembodiment the biomass is contacted with a particulate catalyticmaterial and a heat transfer medium.

It has been found that the thermal conversion of biomass materials maybe carried out at milder conditions of temperature if the process iscarried out in the presence of both a heat transfer medium, for examplean inert particulate inorganic material, and a catalytically activematerial.

In a specific embodiment the particulate inorganic material is used thatis both a heat transfer medium and a catalyst.

In a specific embodiment, the catalytically active material is aninorganic oxide in particulate form. Preferably, the particulateinorganic oxide is selected from the group consisting of refractoryoxides, clays, hydrotalcites, crystalline aluminosilicates, layeredhydroxyl salts, and mixtures thereof.

Examples of refractory inorganic oxides include alumina, silica,silica-alumina, titania, zirconia, and the like. Refractory oxideshaving a high specific surface are preferred. Specifically, preferredmaterials have a specific surface area as determined by the BrunauerEmmett Teller (“BET”) method of at least 50 m²/g.

Suitable clay materials include both cationic and anionic clays.Suitable examples include smectite, bentonite, sepiolite, atapulgite,and hydrotalcite.

Other suitable metal hydroxides and metal oxides include bauxite,gibbsite and their transition forms. Cheap catalytic material may belime, brine and/or bauxite dissolved in a base (NaOH), or natural claysdissolved in an acid or a base, or fine powder cement from a kiln.

The term “hydrotalcites” as used herein include hydrotalcite per se, aswell as other mixed metal oxides and hydroxides having ahydrotalcite-like structure, as well as metal hydroxyl salts.

The catalytically active material may comprise a catalytic metal. Thecatalytic metal may be used in addition to or in lieu of thecatalytically active inorganic oxide. The metal may be used in itsmetallic form, in the form of an oxide, hydroxide, hydroxyl oxide, asalt, or as a metallo-organic compound, as well as materials comprisingrare earth metals (e.g. bastnesite).

Preferably, the catalytic metal is a transition metal, more preferably anon-noble transition metal. Specifically preferred transition metalsinclude iron, zinc, copper, nickel, and manganese, with iron being themost preferred.

There are several ways in which the catalytic metal compound can beintroduced into the reaction mixture. For example, the catalyst may beadded in its metallic form, in the form of small particles.Alternatively, the catalyst may be added in the form of an oxide,hydroxide, or a salt. In one preferred embodiment, a water-soluble saltof the metal is mixed with the carbon based energy source and the inertparticulate inorganic material in the form of an aqueous slurry. In thisparticular embodiment, it may be desirable to mix the particles of thebiomass with the aqueous solution of the metal salt before adding theinert particulate inorganic material, so as to make sure that the metalimpregnates the biomass material. It is also possible to first mix thebiomass with the inert particulate inorganic material, prior to addingthe aqueous solution of the metal salt. In yet another embodiment, theaqueous solution of the metal salt is the first mixed with theparticulate inert inorganic material, whereupon the material is driedprior to mixing it with the particulate biomass In this embodiment, theinert inorganic particles are converted to heterogeneous catalystparticles.

The specific nature of the inert particulate inorganic material is notof critical importance for the process of the present invention, as itsmain function is to serve as a vehicle for heat transfer. Its selectionwill in most cases be based on considerations of availability and cost.Suitable examples include quartz, sand, volcanic ash, virgin (that is,unused) inorganic sandblasting grit, and the like. Mixtures of thesematerials are also suitable. Virgin sandblasting grit is likely to bemore expensive than materials such as sand, but it has the advantage ofbeing available in specific ranges of particle size and hardness.

When used in a fluidized bed process, the inert particulate inorganicmaterial will cause a certain level of abrasion of the walls of thereactor, which is typically made of steel. Abrasion is generallyundesirable, as it causes an unacceptable reduction in the useful lifeof the reactor. In the context of the present invention, a moderateamount of abrasion may in fact be desirable. In case there is abrasion,such abrasion could introduce small particles of metal into the reactionmixture, comprising the metal components of the steel of the reactor(mainly Fe, with minor amounts of, for example, Cr. Ni, Mn, etc.). Thiscould impart a certain amount of catalytic activity to the inertparticulate inorganic material. It will be understood that the term“inert particulate inorganic material” as used herein includes materialsthat are by their nature inert, but have acquired a certain degree ofcatalytic activity as a result of having been contacted with, forexample metal compounds.

Sandblasting grit that has previously been used in a sandblastingprocess is particularly suitable for use in the process of the presentinvention. Used sandblasting grit is considered a waste material, whichis abundantly available at a low cost. Preferred are sandblasting gritmaterials that have been used in the sandblasting of metal surfaces.During the sandblasting process the grit becomes intimately mixed withminute particles of the metal being sandblasted. In many cases thesandblasted metal is steel. Grit that has been used in the sandblastingof steel presents an intimate mixture comprising small particles ofiron, and lesser quantities of other suitable metals such as nickel,zinc, chromium, manganese, and the like. Being in essence a wasteproduct, grit from a sandblasting process is abundantly available at alow cost. Nevertheless, it is a highly valuable material in the contextof the process of the present invention.

The effective contacting of the carbon based energy source, the inertinorganic material and the catalytic material is essential and canproceed via various routes. The two preferred routes are:

The dry route, whereby a mixture of the particulate biomass material andthe inert inorganic material is heated and fluidized, and the catalyticmaterial is added as fine solid particles to this mixture.

The wet route, whereby the catalytic material is dispersed in a solventand this solvent is added to the mixture of particulate biomass materialand the inert inorganic material. A preferred solvent is water.

The term “fine particulate biomass” as used herein refers to biomassmaterial having a mean particle size in the range of from 0.1 mm to 3mm, preferably from 0.1 mm to 1 mm.

Biomass from sources such as straw and wood may be converted to aparticle size in the range of 5 mm to 5 cm with relative ease, usingtechniques such as milling or grinding. For an effective thermalconversion it is desirable to further reduce the mean particle size ofthe biomass to less than 3 mm, preferably less than 1 mm. Comminutingbiomass to this particle size range is notoriously difficult. It has nowbeen discovered that solid biomass may be reduced in particle size to amean particle size range of from 0.1 mm to 3 mm by abrading biomassparticles having a mean particle size in the range of 5 mm to 50 mm in aprocess involving mechanical mixing of the biomass particles with aninorganic particulate material and a gas.

Abrasion of particles in a fluid bed process is a known, and in mostcontexts an undesirable phenomenon. In the present context thisphenomenon is used to advantage for the purpose of reducing the particlesize of solid biomass material.

Thus, in one embodiment of the present invention, biomass particleshaving a particle size in the range of from 5 mm to 50 mm are mixed withinorganic particles having a particle size in the range of from 0.05 mmto 5 mm. This particulate mixture is agitated with a gas. As theinorganic particles have a hardness that is greater than that of thebiomass particles, the agitation results in a reduction of the size ofthe biomass particles. Suitably this process is used for reducing theparticle size of the biomass to 0.1 to 3 mm.

The amount of agitation of the particulate mixture determines to a largeextent the rate of size reduction of the biomass particles. In order ofincreasing abrasion activity, the agitation may be such as to form afluid bed, a bubbling or ebullient bed, a spouting bed, or pneumaticconveyance. For the purpose of the present invention, spouting beds andpneumatic conveyance are the preferred levels of agitation.

The gas may be air, or may be a gas having a reduced level of oxygen (ascompared to air), or may be substantially oxygen-free. Examples includesteam, nitrogen, and gas mixtures as may be obtained in a subsequentthermal conversion of the fine biomass particles. Such gas mixtures maycomprise carbon monoxide, steam, and/or carbon dioxide.

The abrasion process may be carried out at ambient temperature, or at anelevated temperature. The use of elevated temperatures is preferred forbiomass particles containing significant amounts of moisture, because itresults in a degree of drying of the biomass particles. Drying increasesthe hardness of the biomass particles, making the particles moresusceptible to size reduction by abrasion. Preferred drying temperaturesrange from about 50 to 150° C. Higher temperatures are possible, inparticular if the agitating gas is oxygen-poor or substantiallyoxygen-free.

Preferred for use in the abrasion process are those inorganic particlesthat will be used in a subsequent thermal conversion process accordingto the present invention. In a still further preferred embodiment thecatalytic material is also present during the abrasion process. It isbelieved that some of the catalytic material, if present during theabrasion process, becomes embedded in the biomass particles, which makesthe subsequent thermal conversion process more effective.

In a particularly preferred embodiment of the present invention, biomassparticles having a particle size in the range of 5 mm to 50 mm are mixedwith inert inorganic particles and a catalytic material. This mixture isagitated by a gas, preferably resulting in the formation of a spoutingbed or pneumatic conveyance. After the biomass particles reach a meanparticle size in the range of 0.1 mm to 3 mm the temperature isincreased to 150 to 600° C.

The small biomass particles obtained in the abrasion process areparticularly suitable for conversion to a bioliquid in a suitableconversion process. Examples of suitable conversion processes includehydrothermal conversion, enzymatic conversion, pyrolysis, catalyticconversion, and mild thermal conversion.

In an alternate embodiment of step a), particles of the carbon-basedenergy carrier material are covered with the very small particles of acatalytic material. Conceptually, the particles of the carbon-basedenergy carrier material are dusted with a coating of catalyst particles.Although both the energy carrier material and the catalytic material aresolids, by providing catalyst particles that are much smaller than theparticles of the energy carrier material it is possible to provide avery intimate contact between the energy carrier particles and thecatalyst particles. As a result it is possible to catalytically convertat least the outer shell of the energy carrier particles, so as to makethese particles more susceptible to conversion to liquid fuel componentsin a subsequent process.

As a first step, carbon-based energy carrier material is provided in theform of small particles. This may be by the grinding, milling, and thelike. The most suitable method for making these small particles dependson the nature of the carbon-based energy carrier material. For example,coal may be milled in a ball mill or a hammer mill; other materials maybe more conveniently treated in a grinder. The appropriate method may beselected by the skilled person based on general criteria of thefeasibility, cost, and hardness of the material to be ground.

If the energy carrier is tar sand the particles comprise sand grainscoated or partially coated with a heavy hydrocarbon mixture. In generalthese particles already have the appropriate size for the process of thepresent invention. In any event, it is generally not practical to reducethe size of these tar sand particles.

The particle size d_(e) of the particulate carbon-based energy carriermaterial preferably is in the range of from 5 mm to 100 micrometers.

The catalyst material is provided in the form of particles having anaverage particle size d_(c) in the range of from 1000 nm to 10 nm.Particles of this size may be obtained by forming inorganic materialsfrom a solution or a slurry, and controlling the conditions so as tofavor the formation of particles within this size range. Processes ofthis kind are well-known, and are not part of the present invention. Inan alternate process, inorganic materials may be formed into particlesof the desired size by exfoliating or peptizing larger particles.

In a preferred embodiment, the ratio d_(e)/d_(c) is in the range of50,000 to 500. Particle size ratios within these ranges ensure is thatthe particles of the carbon-based energy carrier material may be coatedwith a dusting of particles of the catalytic material.

The particles of the carbon-based energy carrier material and theparticles of the catalyst are mixed together. This mixing may be done byany suitable method known to the skilled person. The appropriate methodwill depend on the nature of the carbon-based energy carrier material.In general, methods used for reducing the particle size of thecarbon-based energy carrier material tend to be also suitable for thismixing step.

Preferably, the energy carrier particles and cut his particles are makesin a weight ratio in the range of from 1000:1 to 10:1, preferably from100:1 to 30:1. These weight ratios ensure that a sufficient number ofcatalyst particles are available to provide at least a partial coatingof the energy carrier particles.

An important aspect of the present invention is the reaction temperaturein step b) of less than 450° C., preferably less than 400° C. Morepreferably the reaction temperature is less than 350° C., still morepreferably less than 300° C., and most preferably less than 250° C. Thisreaction temperature is made possible by using a catalytic materialselected from the group of cationic clays, anionic clays, natural clays,hydrotalcite-like materials, layered materials, ores, minerals, metaloxides, hydroxides and carbonates of the alkaline and alkaline earthmetals, and mixtures thereof.

The catalyst particles are of a size suitable for heterogeneouscatalysis. As a general rule, small catalyst particle sizes arepreferred in heterogeneous catalysis, because the smaller a particle thegreater the fraction of the available atoms that are present at thesurface of the particle. Therefore, particle sizes of less than 100microns are suitable, particles of less than 1,000 nanometers beingpreferred. It is in general not desirable to use particles smaller thanabout 100 nm. Although the catalytic activity of such smaller particlesis greater, it requires disproportionately greater amounts of energy tocreate such small particles, and the small particles make it moredifficult to separate the particles from product streams after catalyticpyrolysis.

The carbon-based energy carrier material may be from mineral, syntheticor biological origin. Materials from mineral origin include heavycrudes, shale oils, tars (e.g., from tar sands) and bitumen. Materialsfrom synthetic origin include waste supplies of synthetic resins. Thesesynthetic resins may be virgin materials, for example rejects frommolding and drawing operations, and used materials, such as recycledpackaging materials. Materials from biological origin include biomass,in particular solid biomass containing cellulose, lignin, andlignocellulose. A preferred biomass is biomass of aquatic origin, suchas algae.

The carbon-based energy carrier material is either a viscous liquid or asolid, making it difficult to establish an intimate contact between thecarbon-based energy carrier material and the particulate catalystmaterial. It may be necessary to mill the carbon-based energy carriermaterial together with the particulate catalyst material. In a preferredembodiment of the process, the particulate catalyst material may be“sand blasted” onto the carbon-based energy carrier material. For thispurpose the particulate catalyst material is taken up in a stream ofinert gas, and the inert gas is caused to flow, e.g., by means of acompressor. In his manner the catalyst particles are given a velocity ofat least 1 m/s, preferably at least 10 m/s.

The stream of gas is then impinged upon the carbon-based energy carriermaterial. Due to their kinetic energy the catalyst particles penetratethe carbon-based energy carrier material, thereby providing thenecessary intimate contact.

The sand blasting of particles onto the carbon-based energy carriermaterial causes mechanical breakup of the latter, which is of particularadvantage if this material is a solid. The effect can be reinforced bymixing the catalyst particles with particulate inert material.Preferably the inert material has a particle size similar to that of thecatalyst material.

In a particularly preferred embodiment of the process, step a) iscarried out in a chemical reactor, such as a fluidized bed reactor, ariser reactor, or a downer reactor. Conveniently, step b) may be carriedout in the same reactor as step a).

In step b) reaction products are formed having molecular weights suchthat these products are in gas or liquid form when at room temperature.At the reaction temperature these reaction products are all in the gasform, which is referred to herein as “reaction products in the vaporphase”. It is an important aspect of the present invention that thereaction products in the vapor phase are quickly separated from theparticulate catalyst material. Specifically, the reaction products inthe vapor phase are separated from the catalyst particles within 10seconds after they are formed, preferably within 5 seconds, morepreferably within 3 seconds. The reaction products generally comprisehydrocarbons and steam.

This separation may be accomplished by applying reduced pressure to thezone of the reactor where this separation takes place. Preferably thereduced pressure is a “vacuum” of less than 500 mBar.

This rapid separation of the reaction products from the catalystmaterial is an important factor in limiting the degradation of thereaction products. Degradation can be diminished further by rapidlycooling the reaction products after they are separated from the catalystmaterial. If the separation step involves applying reduced pressure,some cooling of the reaction products will occur as a result of theiradiabatic expansion. Further cooling may be accomplished by any meansknown in the art, for example by pumping the reaction products through aheat exchanger in counter-flow with a cooling medium, such as chilledwater.

Preferably, the reaction products are cooled to a temperature below 200°C., preferably below 150° C., within 10 seconds, preferably within 3seconds, after being separated from the catalytic material.

Some reaction products remain adsorbed to the catalyst particles afterseparating step c). These materials may be removed by stripping, usingmethods well known in the art. For example, stripping conditions as usedin FCC units are suitable. Although the reaction products removed bystripping may have been in contact with the catalyst material longerthan the desired 10 seconds, these materials are not necessarily fullydeteriorated.

During the reaction coke may form on the catalyst surface. This coke canbe burned off by exposing the catalyst to an oxidative environment, suchas air, at elevated temperature. This optional step may be carried outin a regenerator of the type known from FCC processes.

This burning-off step results in the production of CO₂. In a preferredembodiment this CO₂ is used in the production of biomass, for example byspraying it onto crops or trees under conditions that are favorable forphotosynthesis.

The heat generated during the optional regeneration step may be used tosupply the heat for the endothermic reaction of step b). To this end,hot catalyst particles from the regenerator are recycled to step a) orb) of the process. The amount of coke deposit may be such that theamount of heat generated during the regeneration step may be greaterthan what is needed for fueling the conversion reaction. If this is thecase, excess heat may be removed from the process by cooling thecatalyst particles to a desired temperature prior to recycling them intothe reactor. The desired temperature is determined by the heat balancefor the process, and the desired reaction temperature for step b).Accordingly, the desired temperature of the catalyst particles justprior to recycle may be determined in a manner similar to that used inFCC processes.

If heat is removed from the regenerated catalyst particles, this heatmay be used for generating steam, hot water, or electricity.

In a preferred embodiment the process is carried out in an FCC unit. Itmay be desirable to carry out step a) in a pretreatment reactor, priorto introduction of the carbon-based energy carrier material into theriser of the FCC unit.

In a preferred embodiment of the invention a reactive gas is presentduring at least part of step b). This reactive gas may have oxidative orreductive properties, or the reactive gas may be reactive inisomerisation or alkylation properties. Examples of reactive gaseshaving oxidative properties include air and oxygen, as well as mixturesof oxygen and an inert gas such as nitrogen.

Examples of gases having reductive properties include carbon monoxide,hydrogen sulfide, and hydrogen. Hydrogen may be less preferred, as itmay require a high pressure.

Gases having alkylation or isomerisation properties include iso-butane,naphtene, volatile organic acids, and the like.

A particularly preferred embodiment is illustrated in FIG. 1. The figurerepresents a three-stage process for the mild pyrolysis of acarbon-based energy carrier. The process will be described withreference to biomass, specifically wood chips, as the carbon-basedenergy carrier. It will be understood that this process is suitable forother forms of biomass, as well as for mineral forms of carbon-basedenergy carriers.

FIG. 1 shows a fluid bed drying and grinding unit 10. Particulatebiomass, such as wood chips or saw dust, is introduced into this unit10, and blended with a fluid bed of catalyst particles. This mixing maytake place at ambient temperature, but it is preferred to operate unit10 at an elevated temperature. Preferably the temperature is kept atbelow about 200° C. The mechanical impact of the catalyst particlesimpinging on the biomass particles provides a grinding action, therebyfurther reducing the particle size of the biomass. In addition the fluidflow in the fluid bed provides a degree of drying of the biomassparticles.

From unit 10 the biomass/catalyst mixture is conveyed to downer reactor20. At the top of reactor 20 a stream of catalyst particles isintroduced at elevated temperature, for example 400° C. The biomassstream undergoes catalytic pyrolysis in reactor 20, whereby volatilereaction products and char and coke are formed. Char and coke depositonto the catalyst particles. The volatile reaction products are removedfrom the reactor at the bottom, and separated into non-condensable fluegas (CO, CO₂), and liquid reaction products.

The coke- and char containing catalyst particles are conveyed to fluidbed regeneration unit 30. In unit 30 the char and coke are burned off inan oxygen-containing atmosphere such as oxygen or air. In regenerationunit 30 the temperature rises to well above 400° C., for example toabout 650° C. The hot catalyst stream from regenerator 30 is conveyed toa first heat exchanger 40, where the temperature is reduced to about400° C. Heat recovered from the catalyst stream is utilized to generatesteam, which may be used as-is in other parts of the plant, may beconverted to electric energy and used as such, or sold, etc.

A portion of the catalyst stream from heat exchanger 40 is conveyed tothe top of downer reactor 20. Another portion is conveyed to a secondheat exchanger 50, where it is cooled to the temperature desired fordrying and grinding unit 10, e.g., less than 200° C. Heat recovered fromheat exchanger 50 may be used to generate steam or electric energy, foruse in other parts of the plant, or sold.

It will be understood that the process may be optimized by varying thetemperature at the exit of heat exchanger 40 (and hence the temperatureat the top of reactor 20); the temperature at the exit of heat exchanger50 (and hence the temperature in dryer/grinder 10), the ratio ofcatalyst streams 41 and 51, etc. In general it is desirable to operatereactor 20 at as low a temperature as possible, preferably below 350°C., more preferably below 300° C.

Instead of downer reactor 20 a riser reactor may be used. It will beunderstood that in such an arrangement the catalyst and the feed will beintroduced at the bottom of the reactor, and product and used catalystwill be collected at its top.

Flash Pyrolysis Test

Flash Pyrolysis Tests (FPT) were Carried Out in the Set-Up Shown in FIG.2.

The set-up consisted of a feeding section (4) with an automated valve(5) for N₂ pulsing to convey biomass or biomass/catalyst sample (1) intoa bench-scale cyclonic reactor (2). Heating of the reactor was providedby electrical oven (3) and the temperature was controlled by athermocouple (9). Carrier gas (N₂, 30 l/min) is continuously sent intobottom part of the reactor. Liquefied products were collected in acooler (6) immersed in liquid nitrogen (7). Frozen liquid products thatdid not stick to the cooler walls were collected by micro-filter (8).

Flash pyrolysis of biomass or a biomass/catalyst mixture (1) wasperformed in bench-scale cyclonic reactor (2). The reactor was preheatedby electrical oven (3) to the experiment temperature. During allexperiments the reactor was flashed with N₂ (301/min). Biomass (about 1g) was placed in the feed supply section (4) above the reactor and sentto the reactor with a short pulse of N₂, using automated valve (5). Tocollect liquefied products in a sufficient amount for the followingcharacterization, each experiment contained at least 4 pulses with atleast 1 min between pulses (time required to load new portion of sampleinto the feed section). Liquefied products were collected in a cooler(6) which was kept at minus 196° C. (7). Due to high carrier gas flowsome “frozen” liquid went through the cooler and was collected asparticles by an outlet micro-filter (8). After the micro-filter carriergas and non-condensed products went to vent.

After pyrolysis experiments the cooler and the micro-filter were heatedto room temperature and condensed products were thoroughly washed byacetone (about 750-800 ml of acetone par experiment). Afterwards acetonewas removed using a vacuum rotary evaporator at room temperature.

Chemicals

All chemicals were from Sigma-Aldrich.

Xylan:

Sigma-Aldrich cat No X4252. Name: Xylan from beechwood (synonym:Poly(β-D-xylopyranose[1→4])); Quality >90% xylose residues.Lignin: Sigma-Aldrich cat No 371017. Name: Lignin, organosolv;

Cellulose A: Sigma-Aldrich cat No 43, 523-6; Cellulose

microcrystalline, powder;High purity cellulose powders for partition chromatography.Bulking agent, opacifier, anti-caking agent, extrusion aid andstabilizer for foams and emulsions.Features and Benefits Amorphous regions are hydrolyzed leavingcrystalline microfibrils. Forms thixotropic gels, good thermalstability.Form: microcrystalline powderpH 5-7 (11 wt. %)bulk density 0.6 g/mL (25° C.)

Differential Thermal Gravimetry

Thermal Decomposition of the Samples was Performed Using aMettler-Toledo TGA/SDTA851e Thermobalance. A Simplified Scheme of theUnit is Shown in FIG. 3

Thermobalance 19 is used as follows. The sample (10-15 mg) contained inan aluminum cup (70 ml) (11) was placed on a cup holder (12) whichcontained a thermocouple for measuring the sample temperature. Viasample holder (13) the cup was connected to a balance (14) placed inthermostatic block (15) to provide high quality measurement of thesample weight change under thermal treatment. The sample was heated byelectrical oven (16) up to desired temperature (max 1100° C.) with arequired heating rate (in our experiments 5° C./min). Inert gas (in ourcase Ar) was provided into the oven via a gas capillary (17). Thebalance was protected from possible formation of dangerous gases duringthe experiments by a protective gas supplied continuously via tube (18).

Experiments were conducted with wood particles of Canadian pine (pinuscanadiensis). Particles were obtained from a wood mill in the form ofshavings, having a particle size in the range of 1-10 mm. These shavingswere either milled for 5 minutes in a coffee grinder to a particle sizeof 0.5-1 mm (“pine saw dust”), or to a particle size of about 0.2 mm(“pine powder”) in a planetary high energy mill (Pulverisette 5).

Samples were subjected to temperature programmed heating in theabove-described thermobalance. The weight of the sample was recorded asa function of temperature. The derivative of this curve was alsorecorded (referred to as “DTG signal” in FIGS. 4 through 8). The minimumof this curve corresponds to the inflection point of the TG curve, andprovides an indication of the decomposition temperature (“T_(D)”) of thesample. Experiments were conducted with pure cellulose, xylan (whichserved as a model compound for hemicellulose), pure lignin, pine sawdust, and pine powder.

In order to measure the effect of the addition of a particulateinorganic material samples were ground together with the inorganicparticulate material for 120 minutes in a planetary high energy mill(Pulverisette 5 type). The samples were subjected to temperatureprogrammed decomposition. The decomposition T_(D) temperature and theresidue at 600° C. were recorded. Representative curves are presented inFIGS. 4 to 8.

FIG. 4 shows the DTG curve for pine powder. T_(D) was 345° C.; theresidue was 22 wt %.

FIG. 5 shows the DTG curve for pine powder co-milled with 20% Na₂CO₃.T_(D) was 232° C.; the residue was 24%.

FIG. 6 shows the DTG curve for pine powder co-milled with 20% MgO. T_(D)was 340° C.; the residue was 17%.

FIG. 7 shows the DTG curve for pine powder co-milled with 20% calcinedhydrotalcite. T_(D) was 342° C.; the residue was 19%.

FIG. 8 shows the DTG curve for pine powder co-milled with non-calcinedhydrotalcite. T_(D) was 350° C.; the residue was 13%.

Results from the experiments are collected in Table 1

Sample T_(D) (° C.) % Residue (wt %) Cellulose (pure) 325 10 xylan 27034 lignin (pure) 342 42 pine saw dust 345 34 pine powder 345 22 pine sawdust + 50% Na₂CO₃ 276 34 pine powder + 20% Na₂CO₃ 232 24 pine powder +20% CaCl₂ 295 33 pine powder + 20% NaCl 313 31 pine powder + ZrO₄(SO₄)₃356 19 pine powder + 20% MgO 340 17 pine powder + 20% HTC ⁽¹⁾ 350 13pine powder + 20% CBV300 ⁽²⁾ 335 11 pine powder + 20% 345 20 Zn(OH)CO₃pine powder + 20% HTC ⁽³⁾ 326 21 xylan + 20% ZrO₄(SO₄)₃ 266 30 xylan +20% NaCl 266 30 xylan + 20% LiNO₃ 263 20 ⁽¹⁾ hydrotalcite (non-calcined)⁽²⁾ a commercial silica/alumina/zeolite(Y) catalyst supplied by Zeolyst⁽³⁾ hydrotalcite (calcined), supplied by Reheis

In a separate comparative experiment pine saw dust, pine powder and pinepowder co-milled with 20% Na₂CO₃ were subjected to flash pyrolysis asdescribed above. Flash pyrolysis of pine saw dust and pine powderproduced a black oil of poor quality and smell, and a low pH. Flashpyrolysis of the pine powder sample co-milled with 20% Na₂CO₃ producedan oil that was lighter in color and judged to be of much betterquality.

1. A process for converting a solid or highly viscous carbon-basedenergy carrier material to liquid and gaseous reaction products, saidprocess comprising the steps of: a) contacting the carbon-based energycarrier material with a particulate catalyst material b) converting thecarbon-based energy carrier material at a reaction temperature between200° C. and 450° C., thereby forming reaction products in the vaporphase; c) separating the vapor phase reaction products from theparticulate catalyst material within 10 seconds after said reactionproducts are formed; d) optionally quenching the reaction products to atemperature below 200° C.
 2. The process of claim 1 comprising theadditional step of stripping reaction products from the particulatecatalyst material.
 3. The process of claim 1 or 2 comprising theadditional step of burning off any coke formed on the particulatecatalyst material.
 4. The process of claim 2 or 3 comprising the furtherstep of recycling the particulate catalyst material to step a) or b). 5.The process of any one of the preceding claims whereby a reactive gas ispresent during step b).
 6. The process of claim 5 wherein the reactivegas has oxidative or reductive properties.
 7. The process of claim 5wherein the reactive gas is reactive in isomerisation or alkylationreactions.
 8. The process of claim 6 wherein the reactive gas comprisesoxygen, hydrogen, hydrogen sulfide, or carbon monoxide.
 9. The processof claim 7 wherein the reactive gas comprises iso-butane, naphtene, or avolatile organic acid.
 10. The process of any one of the precedingclaims wherein the catalytic material comprises cationic clays, anionicclays, natural clays, hydrotalcite-like materials, layered materials,ores, minerals, metal oxides, hydroxides and carbonates of the alkalineand alkaline earth metals, or mixtures thereof.
 11. The process of anyone of the preceding claims wherein the carbon-based energy carriermaterial is of mineral origin.
 12. The process of claim 11 wherein thecarbon-based energy carrier material is a tar, a heavy crude, or abitumen.
 13. The process of any one of claims 1 through 10 wherein thecarbon-based energy carrier material is a synthetic polymer.
 14. Theprocess of any one of claims 1 through 10 wherein the carbon-basedenergy carrier material is a solid biomass.
 15. The process of claim 14wherein the solid biomass comprises cellulose, lignin, orlignocellulose.
 16. The process of claim 14 wherein the solid biomass isof aquatic origin.
 17. The process of any one of claims 3-16 whereby theCO₂ is utilized in the production of biomass.
 18. The process of claim17 whereby the CO₂ is utilized in the production of aquatic biomass. 19.The process of any one of the preceding claims wherein step a) comprisesmilling of the carbon-based energy carrier material in the presence ofthe particulate catalyst material.
 20. The process of any one of thepreceding claims wherein step a) comprises the steps of: (i) taking upthe particulate catalyst material in a stream of a carrier gas; (ii)causing the gas stream to flow such that the particulate catalystmaterial reaches a velocity of at least 1 m/s, preferably at least 10m/s (iii) impinging the catalyst particles onto the carbon-based energycarrier material.
 21. The process of claim 17 wherein the carrier gasfurther comprises a particulate inert material.
 22. The process of claim17 or 18 wherein step a) is carried out in a fluidized bed, a riserreactor, or a downer reactor.
 23. The process of any one of thepreceding claims wherein the reaction temperature in step b) is lessthan 350° C., preferably less than 300° C., more preferably less than250° C.
 24. The process of any one of the preceding claims wherein thevapor phase reaction products comprise steam, hydrocarbons, or a mixturethereof.
 25. The process of claim 3 wherein the coke is burned off withair.
 26. The process of claim 3 or 22 comprising the further step ofcooling the particulate catalyst material after the coke has been burnedoff.
 27. The process of claim 23 whereby heat recovered from theparticulate catalyst material is used for generating steam, hot water,or electricity.
 28. The process of any one of the preceding claimswhereby at least step b) is carried out in an FCC unit.
 29. The processof any one of the preceding claims whereby at least step b) is carriedout in a downer.